[nmotz]

Yeah the learning point here is that there is NO set percentage of water volume that you need to change and NO definite frequency of water changes. It's going to depend on your individual tank. Having said that, you probably do not need quite that much water changed. It would certainly save some money on salt if you decreased that a bit. But if you make an adjustment to your water change schedule, you'll want to carefully observe for any potential problems.

Some tanks seem to need more water changes than others. Mine gets cranky if I change the water weekly, but also doesn't seem to like going more than 3 weeks. Just try some different options and see if they work.